Cryosurgical probe with bellows shaft

ABSTRACT

The malleable cryosurgical probe includes a cryostat assembly and a cryoprobe assembly. The cryostat assembly includes an elongated shaft assembly having a bellows portion thereof and a closed distal end. The shaft assembly includes at least one freezing portion comprising the bellows portion, at least one thermally insulated portion and a thermally insulating element positioned about the thermally insulated portion. A cryostat is operably associated with the elongated shaft assembly. It includes a cryostat inlet for receiving gas entering the cryostat, a cryostat outlet and a heat exchanger positioned between the cryostat outlet and the cryostat inlet. The heat exchanger receives gas from the cryostat inlet and provides heat transfer between gas flowing within the cryostat and fluid exterior thereto. At least one Joule-Thomson nozzle is in fluid communication with the cryostat outlet. The at least one Joule-Thomson nozzle expands gas expelled therefrom. The expanded cold fluid communicates with the freezing portion to provide cooling thereof. The cryoprobe assembly includes a handle assembly for supporting the cryostat assembly and a fluid supply line assembly connectable to a fluid source at one end and to the cryostat inlet at a second end. The heat exchanger is positioned at a location longitudinally spaced from the freezing portion(s).

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Ser. No. 10/057,033 filedJan. 13, 2002, which is a continuation-in-part of U.S. Ser. No.09/957,337 filed Sep. 20, 2001.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to cryosurgical probes and more particularly to acryosurgical probe that includes an improved malleable shaft for usewith applications in which a desired angle of entry and contact with thepatient's organ is required.

2. Description of the Related Art

Cryosurgical probes are used to treat a variety of diseases. Thecryosurgical probes quickly freeze diseased body tissue, causing thetissue to die after which it will be absorbed by the body, expelled bythe body, sloughed off or replaced by scar tissue. Cryothermal treatmentis currently used to treat prostate cancer and benign prostate disease,breast tumors including breast cancer, liver tumors including cancer,glaucoma and other eye diseases. Cryosurgery may also be used for thetreatment of a number of other diseases and conditions including thetreatment of cardiac arrhythmias, such as atrial fibrillation.

A variety of cryosurgical instruments variously referred to ascryoprobes, cryosurgical probes, cryosurgical ablation devices, andcryostats and cryocoolers, have been available for cryosurgery. Thesedevices typically use the principle of Joule-Thomson expansion togenerate cooling. They take advantage of the fact that most fluids, whenrapidly expanded, become extremely cold. In these devices, a highpressure gas such as argon or nitrogen is expanded through a nozzleinside a small cylindrical shaft or sheath typically made of steel, andthe Joule-Thomson expansion cools the steel sheath to a cold temperaturevery rapidly.

An exemplary device is illustrated in Sollami, Cryogenic SurgicalInstrument, U.S. Pat. No. 3,800,552 (Apr. 2, 1974). Sollami shows abasic Joule-Thomson probe with a sheath made of metal, a fin-tubehelical gas supply line leading into a Joule Thomson nozzle whichdirects expanding gas into the probe. Expanded gas is exhausted over thefin-tube helical gas supply line, and pre-cools incoming high pressuregas. For this reason, the coiled supply line is referred to as a heatexchanger, and is beneficial because, by pre-cooling incoming gas, itallows the probe to obtain lower temperatures.

Ben-Zion, Fast Changing Heating and Cooling Device and Method, U.S. Pat.No. 5,522,870 (Jun. 4, 1996) applies the general concepts ofJoule-Thomson devices to a device that is used first to freeze tissueand then to thaw the tissue with a heating cycle. Nitrogen is suppliedto a Joule-Thomson nozzle for the cooling cycle, and helium is suppliedto the same Joule-Thomson nozzle for the warming cycle. Preheating ofthe helium is presented as an essential part of the invention, necessaryto provide warming to a sufficiently high temperature.

A Joule-Thomson cryostat for use as a gas tester is illustrated inGlinka, System for a Cooler and Gas Purity Tester, U.S. Pat. No.5,388,415 (Feb. 14, 1995). Glinka also discloses use of the by-pass fromthe Joule-Thomson Nozzle to allow for cleaning the supply line, and alsomentions that the high flow of gas in the by-pass mode will warm theprobe. This is referred to as mass flow warming, because the warmingeffect is accomplished purely by conduction and convection of heat tothe fluid mass flowing through the probe.

Various cryocoolers use mass flow warming, flushed backwards through theprobe, to warm the probe after a cooling cycle. Lamb, RefrigeratedSurgical Probe, U.S. Pat. No. 3,913,581 (Aug. 27, 1968) is one suchprobe, and includes a supply line for high pressure gas to aJoule-Thomson expansion nozzle and a second supply line for the same gasto be supplied without passing through a Joule-Thomson nozzle, thuswarming the catheter with mass flow. Longsworth, Cryoprobe, U.S. Pat.No. 5,452,582 (Sep. 26, 1995) discloses a cryoprobe which uses thetypical fin-tube helical coil heat exchanger in the high pressure gassupply line to the Joule-Thomson nozzle. The Longsworth cryoprobe has asecond inlet in the probe for a warming fluid, and accomplishes warmingwith mass flow of gas supplied at about 100 psi. The heat exchanger,capillary tube and second inlet tube appear to be identical to thecryostats previously sold by Carleton Technologies, Inc. of OrchardPark, N.Y.

Each of the above mentioned cryosurgical probes builds upon prior artwhich clearly establishes the use of Joule-Thomson cryocoolers, heatexchangers, thermocouples, and other elements of cryocoolers. Walker,Miniature Refrigerators for Cryogenic Sensor and Cold Electronics (1989)(Chapter 2) and Walker & Gingham, Low Capacity Cryogenic Refrigeration,pp. 67 et seq. (1994) show the basic construction of Joule-Thomsoncryocoolers including all of these elements. The Giaque-Hampson heatexchanger, characterized by coiled finned-tube, transverse flowrecuperative heat exchanger is typical of cryocoolers. The open mandrelaround which the finned tube coil is placed is also typical ofcryocoolers.

U.S. Pat. Nos. 5,800,487 and 6,074,412, both entitled Cryoprobe, issuedto Mikus et and assigned to the present assignee disclose cryoprobesusing Joule-Thomson nozzles and finned tube helical coil heatexchangers.

Cryosurgical probes may be used, as mentioned above, to treat diseasesof the prostate, liver, and breast, and they have gynecologicalapplications as well. The cryosurgical probes form iceballs which freezedisease tissue. Each application has a preferred shape of iceball,which, if capable of production, would allow cryoablation of thediseases tissue without undue destruction of surrounding healthy tissue.For example, prostate cryoablation optimally destroys the lobes of theprostate, while leaving the surrounding neurovascular bundles, bladderneck sphincter and external sphincter undamaged. The prostate is widerat the base and narrow at the apex. A pear or fig shaped ice ball isbest for this application. Breast tumors tend to be small and spherical,and spherical iceballs will be optimal to destroy the tumors withoutdestroying surrounding breast tissue. Liver tumors may be larger and ofa variety of shapes, including spherical, olive shaped, hot dog shapedor irregularly shaped, and may require more elongated iceballs, largericeballs, and iceballs of various shapes.

During open chest surgery transmural cryo-lesions can be created on orin the heart to treat cardiac arrhythmia (including atrialfibrillation). A suitable cryoprobe would be useful for thisapplication. Due to the nature of the procedure and anatomical locationsthat lesions must be placed, the cryoprobe must be sufficientlymalleable by the surgeon to be placed on the heart surface but stiffenough such that pressure can be applied without flexing the shaft.

The prior art includes references to malleable and flexible cryoprobes.For example, U.S Pat. No. 6,161,543, issued to Cox et al discloses theuse of a malleable probe. The probe has a malleable shaft. A malleablemetal rod is coextruded with a polymer to form the shaft. The rodpermits the user to shape the shaft as necessary so that a tip can reachthe tissue to be ablated.

U.S. Pat. No. 5,108,390, issued to Potocky et al discloses a highlyflexible cryoprobe that can be passed through a blood vessel and intothe heart without external guidance other than the blood vessel itself.

Several patents disclose the use of bellows-type assemblies for use withcryosurgical systems. For example, U.S. Pat. No. 6,241,722, issued toDobak et al, discloses a cryogenic catheter with a bellows and whichutilizes a longitudinally movable Joule-Thomson nozzle of expansion. TheDobak '722 device preferably uses closed media-flow pathways forefficient recycling of the media employed.

Dobak, in his U.S. Pat. No. 5,957,963, disclose the used of a flexiblecatheter inserted through the vascular system of a patient to place thedistal tip of the catheter in an artery feeding a selected organ of thepatient. The '963 patent discloses a heat transfer bellows for coolingthe blood flowing through the artery.

U.S. Pat. No. 6,235,019, issued to J. W. Lehmann et al, discloses acryosurgical catheter having a bellows. The cryogenic catheter has anelongate outer member and a plurality of inner members disposed with theelongate outer member. The inner members define at least one cryogenicpath through the outer member. At least one of the inner members has atleast one controllable opening formed thereon to selectively releasecryogenic fluid. The inner members also include an overtube and aninjection tube slideably disposed to one another.

U.S. Pat. No. 6,106,518, issued to Wittenberger et al, discloses amedical device that includes a flexible member having a variablegeometry tip with a thermally-transmissive region. A smooth fluid pathis provided through the flexible member to and from a variable geometry,thermally-transmissive region. The thermally-transmissive region may bea bellows-like structure.

U.S. Pat. No. 6,224,624, issued to Lasheras et al, discloses a bellowsstructure used for a selective organ heat transfer device having aflexible coaxial catheter capable of insertion into a selected feedingartery in the vascular system of a patient.

SUMMARY

In a broad aspect, the present invention is a malleable cryosurgicalprobe comprising a cryoassembly for providing a flow of cryogenic fluidand a malleable shaft secured to and in heat transfer relationship withthe cryoassembly. The shaft has a bellows portion located thereon formedof a thermally conductive metal. The bellows portion has a plurality ofconvolutions, the convolutions having outer diameters in a range of0.140-0.180 inches, and inner diameters in a range of 0.065-0.100inches. The bellows portion has a minimum bend radius of about 0.195inches, thus being bendable as desired by the operator.

In another broad aspect, the cryosurgical probe includes a cryostatassembly and a cryoprobe assembly. The cryostat assembly includes anelongated shaft assembly having a bellows portion thereof and a closeddistal end. The shaft assembly includes at least one freezing portioncomprising said bellows portion, at least one thermally insulatedportion and a thermally insulating element positioned about thethermally insulated portion. A cryostat is operably associated with theelongated shaft assembly. It includes a cryostat inlet for receiving gasentering the cryostat, a cryostat outlet and a heat exchanger positionedbetween the cryostat outlet and the cryostat inlet. The heat exchangerreceives gas from the cryostat inlet and provides heat transfer betweengas flowing within the cryostat and fluid exterior thereto. At least oneJoule-Thomson nozzle is in fluid communication with the cryostat outlet.The at least one Joule-Thomson nozzle expands gas expelled therefrom.The expanded cold fluid communicates with the freezing portion toprovide cooling thereof. The cryoprobe assembly includes a handleassembly for supporting the cryostat assembly and a fluid supply lineassembly connectable to a fluid source at one end and to the cryostatinlet at a second end. The heat exchanger is positioned at a locationlongitudinally spaced from the freezing portion(s).

Positioning of the heat exchanger in a position longitudinally spacedfrom the freezing portion(s) provides the capability of providingmalleable segments. The heat exchanger can be made relatively large andpowerful providing enhanced operation while concomitantly providing fora freezing portion and/or thermally insulated portion of the elongatedshaft assembly that has a small diameter. The bellows portion formed ofmaterial that permits reshaping and bending of the elongated shaftassembly as a unit to reposition the ablating surface for greaterablation precision. Moreover, enhancements are disclosed for assuringthat there can be bending and reshaping without kinking or collapsing.Such properties are especially imperative for such devices employed inthe formation of transmural lesions in anatomical locations that areparticularly difficult to access. The malleable segment is sufficientlymalleable to be fashioned to the desired shape while rigid enough toretain the shape during clinical use.

Other objects, advantages, and novel features will become apparent fromthe following detailed description of the invention when considered inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a crossectional view of a preferred embodiment of thecryosurgical probe of the present invention.

FIG. 2 is a crossectional view of the bellows shaft of the cryosurgicalprobe of the present invention.

FIG. 3 is an enlarged crossectional view of a portion of the bellowsshaft of the present invention to show the convolutions.

FIG. 4 is an enlarged crossectional view of the tip of the bellowsshaft.

FIG. 5 is an enlarged view of the cryostat assembly of the cryosurgicalprobe of FIG. 1 with the handle removed for the purposes of clarity.

FIG. 6 is a schematic view of the heart with the cryosurgical probe ofthe present invention shown positioned thereagainst for the treatment ofarrhythmias.

FIG. 7 is a schematic illustration of an embodiment of the cryosurgicalprobe having a movable, thermally insulated main portion.

The same parts or elements throughout the drawings are designated by thesame reference characters.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings and the characters of reference marked thereonFIG. 1 illustrates a preferred embodiment of the present invention,designated generally as 10. The malleable cryosurgical probe 10 includesa cryoassembly, designated generally as 11, for providing a flow ofcryogenic fluid and a malleable shaft assembly, designated generally as12. The malleable shaft assembly 12 is in heat transfer relationshipwith the cryoassembly 11. The shaft includes a bellows portion 13 formedof thermally conductive metal. The cryoassembly 11 will be discussed indetail below.

Referring now to FIGS. 2 and 3 the shaft assembly 12 is illustrated. Asbest seen in FIG. 3 the bellows portion 13 of the shaft assembly 12includes a plurality of convolutions 15. These convolutions 15 haveouter diameters (OD's) preferably in a range of 0.140-0.180 inches andinner diameters (ID's) preferably in a range of 0.065-0.100 inches. Thebellows portion 13 has a minimum bend radius of about 0.195 so that thebellows portion is bendable as desired by the operator. It is preferablyformed by hydroforming techniques.

Each convolution 15 comprises a peak section 17 and a valley section 19.The peck sections each have peaks such that the convolutions, containingthese alternating peak sections 17 and valley sections 19, arepreferably spaced in a range of 0.020-0.100 inches, peak-to-peak (P-P).Preferably, the convolutions 15 are spaced in a range of 0.030 inches,peak-to-peak. The wall thickness is preferably in a range of 0.0015 to0.0122 inches.

As can be seen most clearly in FIG. 4 a tip portion 21 is located at thedistal end of the shaft assembly wherein the distance between the tip ofthe tip portion and the bellows portion is preferably no more than 1½ ofthe OD's of the convolutions 15.

Referring again to FIG. 1 and also now to FIG. 5 it can be seen that thecryosurgical probe 10 may be deemed to include a cryostat assembly and acryoprobe assembly. The cryostat assembly includes the elongated shaftassembly 12, a cryostat designated generally as 14, and Joule-Thomsonnozzles 16. The cryoprobe assembly includes a handle assembly,designated generally as 18 and a fluid supply line assembly 20.

The elongated shaft assembly 12 includes a main body portion 22 and adistal portion 24 welded thereto with a spacer 26. The main body portion22 includes a thermally protected segment 28 and an adapter segment 30,these two segments being welded together with a spacer 32. The thermallyprotected segment 28 is positioned between the adapter segment 30 andthe distal portion 24. The distal portion 24 comprises the malleablebellows portion 13. Both the main body portion 22 and the distal portion24 are generally tubular elements. They may be formed of, for example,annealed metals such as annealed stainless steel, annealed nickel orannealed copper. The elongated shaft assembly may have a wide range oflengths depending on the desired purpose, i.e. it might be one toperhaps twenty inches long.

A shaft enhancement element such as a spring coil member 36 may bepositioned about the tube of the thermally protected segment 28. Thespring coil member 36 enhances the capability of the thermally protectedsegment 28 of bending and reshaping without kinking or collapsing.

The elongated shaft assembly includes a thermally insulating element 38positioned over the main body portion 22 to define a thermally insulatedportion. The portion of the distal portion 24 that remains uncovered andincludes the bellows portion 13 defines a freezing portion. The freezingportion is preferably made of a thermally conductive material, such asstainless steel, as noted above. The elongated shaft assembly 12 hasbeen shown with three different parts, i.e. segment 28, adapter segment30 and distal portion 24. This is to accommodate various desired sizesof distal portions 24. However, use of these three parts has been shownby way of illustration and not limitation. For example, a one-pieceshaft can be utilized. The thermally insulated portion typically has anouter diameter in a range of between about 0.04 inches and about 0.50inches, preferably in a range of about 0.10 inches and about 0.15inches.

The cryostat 14 comprises a coiled heat exchanger 40. A cryostat inlet42 receives gas entering the cryostat while a cryostat outlet 44provides the gas to the Joule-Thomson nozzles 16. The coiled heatexchanger 40 is coiled around a mandrel 46. In between each winding ofthe heat exchanger, gaps are formed between the coil and the main bodyportion 22, and gaps are formed between the coil and the mandrel 46.This construction is known as a Giaque-Hampson heat exchanger. The heatexchanger, which is an integral part of the high pressure gas pathway,is made with finned tubing, with numerous fins throughout its length.

The handle assembly 18 includes an anchor 48 securely connected to thecryostat assembly by welding or other conventional means. An o-ring 50prevents fluid from escaping through the handle assembly 18. A handle,designated generally as 52, includes two elongated opposing handle bodyelements 54 with radially inward extensions 56 for engaging the spacebetween radially outward extensions 58 of the anchor 48. A handle nozzle60 fits over and secures the handle body elements 54 together at firstends thereof via a friction fit. A handle barb 62 secures the handlebody elements 54 together at second ends thereof.

The fluid supply line assembly 20 includes a housing 64 that supports afluid supply line 66. A temperature measurement device, i.e. athermocouple 68, is positioned within the elongated shaft assembly,extends through the fluid supply line assembly 20 and is connectable toa data acquisition system. The thermocouple 68 is used to measure andmonitor the temperature inside the cryosurgical probe.

Fluid flow through the cryosurgical probe is as follows. High pressurefluid, preferably gaseous argon, and generally at a pressure in a rangeof about 2000 psi to about 4500 psi, typically about 3000 psi, issupplied to the assembly through high pressure fitting 70, flows throughgas supply line 66, through cryostat inlet 42, into heat exchanger 40,through cryostat outlet 44 and Joule-Thomson nozzles 16. (In a preferredembodiment, for the treatment of arrythmia, five Joule-Thomson nozzlesare utilized.) The high pressure gas expands within the expansionchamber and cools to cryogenic temperatures. The temperature at theJoule-Thomson nozzles 16 is generally at a first temperature of about20° C. and expands to a temperature of about −150° C. Condensation ofthe gas is preferably avoided but can be tolerated. After expanding, thegas is at lower pressure and exhausts over the exhaust gas pathway thatincludes flow over outside of the coils of the heat exchanger 40.Because it is now cold, it cools the gas flowing inside the coils. Thismakes cooling more efficient and achieves colder temperatures. Afterpassing through the heat exchanger, the exhaust gas flows through theremainder of the exhaust gas pathway, as indicated by numeraldesignation 70. The exhaust gas is eventually vented to the atmosphere.

Prior art warming methods such as exhaust blocking, reverse flow heattransfer, and electrical heating can be employed. The preferred methodof warming is to supply high pressure helium gas through the supplyline, heat exchanger and Joule-Thomson nozzle. Helium gas heats up whenexpanded through the gas outlet. Thus, the supply of gas to the probecan be switched from high pressure nitrogen or argon to high pressurehelium to effect rapid re-warming of the cryosurgical probe.

Referring now to FIG. 6, the utilization of the present cryosurgicalprobe 10, positioned against the heart 72, for treating arrhythmias, isillustrated. This creates transmural lesions that have the effect ofchanneling, limiting or blocking electrical transmissions. Its malleablecharacteristics allow the cryosurgical probe 10 to create elongatedhomogenous lesions (either curved or straight) at desired locations thatare often difficult to access with a straight surgical implement.

For such treatment of arrhythmia the bellows portion 13 should may be ina range of about 1.5-4.0 inches long, preferably in a range of about2.6-3.2 inches long. The preferred length is about 2.7 inches.

Use of the longitudinally spaced Joule-Thomson nozzles 16 provides theability to create elongated iceballs as desired along the length of thebellows portion 13. Although the embodiment illustrated shows fourJoule-Thomson nozzles 16, more or less can be provided depending on theparticular requirements. Use of this plurality of Joule-Thomson nozzles16 is made possible, in part, because of the spacing of the heatexchanger from them.

Referring now to FIG. 7 another embodiment of the cryosurgical probe isillustrated, designated generally as 74. In this embodiment a slidingassembly including a sliding element 76 attached to a thermal insulatingelement 78 is utilized to cover the bellows portion as desired tocontrol ice formation. The sliding element includes a button 80 toprovide ease in such adjustments.

Obviously, many modifications and variations of the present inventionare possible in light of the above teachings. It is, therefore, to beunderstood that within the scope of the appended claims, the inventionmay be practiced otherwise than as specifically described.

1. A malleable cryosurgical probe, comprising: a cryoassembly forproviding a flow of cryogenic fluid; and, a malleable shaft secured toand in heat transfer relationship with said cryoassembly, said shafthaving a bellows portion located thereon formed of a thermallyconductive metal, said bellows portion having a plurality ofconvolutions, said convolutions having outer diameters in a range of0.140-0.180 inches and inner diameters in a range of 0.065-0.100 inches,said bellows portion having a minimum bend radius of about 0.195 inches,wherein said bellows portion is bendable as desired by the operator. 2.The malleable cryosurgical probe of claim 1, wherein said convolutionseach comprise peak sections and valley sections, said peak sections eachhaving peaks, said convolutions being spaced in a range of 0.020-0.100inches, peak-to-peak.
 3. The malleable cryosurgical probe of claim 1,wherein said convolutions each comprise alternating peak sections andvalley sections, said peak sections each having peaks, said convolutionsbeing spaced in a range of 0.030 inches, peak-to-peak.
 4. The malleablecryosurgical probe of claim 1, wherein said convolutions each comprisealternating peak sections and valley sections, each valley sectiondefining a valley radius and each peak section defining a peak radius,the summation of said valley radius and said peak radius being one-halfthe peak-to-peak distance between convolutions.
 5. The malleablecryosurgical probe of claim 1, wherein each convolution has a wallthickness in a range of 0.0015 to 0.0122 inches.
 6. The malleablecryosurgical probe of claim 1, wherein said shaft comprises a tipportion at a distal end thereof wherein the distance between a tip ofsaid tip portion and said bellows portion is no more than 1½ times theouter diameters of said convolutions.
 7. The malleable cryosurgicalprobe of claim 1, wherein said cryoassembly comprises a plurality oflongitudinally spaced Joule-Thomson nozzles.
 8. The malleablecryosurgical probe of claim 1, wherein said cryoassembly comprises asliding assembly including a sliding element attached to a thermalinsulating element for selectively effecting the location of thefreezing zone.
 9. The malleable cryosurgical probe of claim 1 whereinsaid bellows portion has a length in a range of 1.4 inches to about 4.0inches.
 10. The malleable cryosurgical probe of claim 7 wherein saidcryogenic fluid is introduced to said Joule-Thomson nozzles at a rate ofbetween about 2000 psi to about 4500 psi.
 11. A malleable shaft forutilization with a cryosurgical probe, comprising: a bellows portionlocated thereon formed of a thermally conductive metal, said bellowsportion having a plurality of convolutions, said convolutions havingouter diameters in a range of 0.140-0.160 inches, inner diameters in arange of 0.065-0.100 inches, said bellows portion having a minimum bendradius of about 0.195 inches, wherein said bellows portion is bendableas desired by the operator.
 12. The malleable shaft of claim 11, whereinsaid convolutions each comprise peak sections and valley sections, saidpeak sections each having peaks, said convolutions being spaced in arange of 0.020-0.100 inches, peak-to-peak.
 13. The malleable shaft ofclaim 11, wherein said convolutions each comprise alternating peaksections and valley sections, said peak sections each having peaks, saidconvolutions being spaced in a range of 0.030 inches, peak-to-peak. 14.The malleable shaft of claim 11, wherein said convolutions each comprisealternating peak sections and valley sections, each valley sectiondefining a valley radius and each peak section defining a peak radius,the summation of said valley radius and said peak radius being one-halfthe peak-to-peak distance between convolutions.
 15. A malleablecryosurgical probe, comprising: a) a cryostat assembly, comprising: i)an elongated shaft assembly having at least one malleable bellowsportion thereof and a closed distal end, said shaft assembly, including:at least one freezing portion comprising said at least one bellowsportion; at least one thermally insulated portion; and, a thermallyinsulating element positioned about said thermally insulated portion;ii) a cryostat operably associated with said elongated shaft assembly,comprising: a cryostat inlet for receiving gas entering said cryostat; acryostat outlet; and, a heat exchanger positioned between said cryostatoutlet and said cryostat inlet, said heat exchanger for receiving gasfrom said cryostat inlet and providing heat transfer between gas flowingwithin said cryostat and fluid exterior thereto; and, iii) a pluralityof longitudinally spaced Joule-Thomson nozzles in fluid communicationwith said cryostat outlet, said plurality of Joule-Thomson nozzles forexpanding gas expelled therefrom, the expanded cold fluid communicatingwith said at least one freezing portion to provide cooling thereof; and,b) a cryoprobe assembly, comprising: a handle assembly for supportingsaid cryostat assembly; and, a fluid supply line assembly connectable toa fluid source at one end and to said cryostat inlet at a second end,wherein said heat exchanger is positioned at a location longitudinallyspaced from said at least one freezing portion.
 16. The malleablecryosurgical probe of claim 15, wherein said bellows portion is formedof a thermally conductive metal, said bellows portion having a pluralityof convolutions.
 17. The malleable cryosurgical probe of claim 16,wherein said convolutions each comprise peak sections and valleysections, said peak sections each having peaks, said convolutions beingspaced in a range of 0.020-0.100 inches, peak-to-peak.
 18. The malleablecryosurgical probe of claim 16, wherein said convolutions each comprisealternating peak sections and valley sections, said peak sections eachhaving peaks, said convolutions being spaced in a range of 0.030 inches,peak-to-peak.
 19. The malleable cryosurgical probe of claim 16, whereinsaid convolutions each comprise alternating peak sections and valleysections, each valley section defining a valley radius and each peaksection defining a peak radius, the summation of said valley radius andsaid peak radius being one-half the peak-to-peak distance betweenconvolutions.
 20. The malleable cryosurgical probe of claim 16, whereinsaid at least one Joule-Thomson nozzles comprises a plurality oflongitudinally spaced Joule-Thomson nozzles.
 21. The malleablecryosurgical probe of claim 16, wherein said cryostat assembly comprisesa sliding assembly including a sliding element attached to saidthermally insulating element for selectively effecting the location ofthe freezing zone.
 22. The malleable cryosurgical probe of claim 15,wherein said handle assembly defines a volume formed therein, said heatexchanger being positioned within said volume.
 23. The malleablecryosurgical probe of claim 15, wherein said thermally insulatingelement is adjustably positionable to control the location, size andshape of said freezing portion.